I recently began to wonder is all this effort in efficiency, solar, etc worthwhile…or just wasting time over pennies saved? So I decided to look at the big picture and see what I spend on energy versus an average neighbor and how much CO2 difference that makes.
Our utility (PSE) shows average neighbor energy use. Those neighbors are selected to match our home – single family homes of about 2700 square feet, within 1.8mi, natural gas heat, and an average 4 occupants. From that average usage data we can figure out energy spend for electricity and natural gas.
I also wanted to consider the cars – gas is a huge part of people’s energy expenditures which is easy to overlook without a monthly bill. We drive about 20,000 miles annually on our electric vehicles, so I’ll figure my “average” neighbor will drive the same 20k miles in a car getting 25MPG (the 2018 average for new vehicles according to the EPA). I’m also going to assume the average price of gas is $3/gallon which is a pretty typical price for Western Washington (if not low).
| Our House | Average Neighbor | CO2 Difference | |
| Annual Electric Cost | $520 | $1333 | 7404 lbs |
| Annual Natural Gas Cost | $494 | $950 | 5798 lbs |
| Annual Gasoline Cost | $0 | $2400 | 16000 lbs |
| Annual Total | $1014 | $4683 | 29202 lbs |
Now in fairness what’s missing is the solar array cost. The cost of the array plus loan interest, minus incentives divided by the 25 year life means the solar array costs $590/year. But I decided instead of looking at it annually, lets look at the entire energy spend over 25 years.
You might also wonder if we spend $520/year on PSE power and $590 on solar power…aren’t we spending almost as much on power as my average neighbor? Yes but we actually use more power than our average neighbor not because of inefficiency but because that’s powering the house and two cars.
So back to the 25 year analysis, over long periods I think its worth considering inflation as well. For example PSE natural gas has gone up ~11% last year and PSE was seeking another ~7% this year for gas and electricity. Obviously that doesn’t happen every year but I’m going to assume a fairly modest 2% based on historical averages. In fairness its unlikely anyone’s energy use will remain constant over 25 years, but efficiency improvements may very well get offset by more electronics, more cooling, etc.
| Our House | Average Neighbor | |
| 25 Year Energy Spend Assuming 2% inflation | $32,500 | $150,000 |
| Solar Array Cost Including Loan Interest and Incentives | $14,878 | $0 |
| 25 Year Energy Spend | $47,378 | $150,000 |
Which brings us back to the title of this article, that’s $100,000 in the pocket of the efficient homeowner vs. the average home. So yes, energy efficiency is worth the effort not just for environmental impact but cost of living.